This invention relates to meters which are employed to measure various quantities and indicate, by means of a pointer sweeping across a graduated scale, the level of its particular parameter present at a particular point in time and, more specifically, to the manner in which such meters are encased for protection of the delicate components of those meters and for mounting of those meters in the environment in which they will operate.
Meters are used to measure such diverse parameters as electrical potential, electrical current, fluid pressure, and fluid speed. Often times, the basic meter movement mechanism for measuring different parameters, such as electrical properties or fluid properties, is the same meter movement. Adaptation of that basic meter movement to measure a particular parameter is accomplished by varying the manner in which the meter movement is connected to the environment in which the particular parameter is to be measured. For example, an electrical meter may be associated with a bridge circuit to indicate potential difference or the same basic meter movement may be connected to an amplifier and a detecting device to indicate such parameters as pressure, heat or the like. Additionally, meters may be used as gauges for comparative purposes rather than parameter measurement. Therefore, the only difference between two meters intended to measure two different parameters may often be the difference in the graduated scales across which the pointers of the respective meters will sweep when those meters react to the given environments they are measuring.
The meter movements and pointers of such meters are extremely delicate and prone to being damaged or rendered unacceptably inaccurate by physical contact with them, such as may be experienced in inserting a different scale to accommodate a new application of that meter. By designing a meter which would accommodate interchanging of scales while precluding any possibility of physically contacting the meter movement or the pointer, one could realize significant economies in manufacturing such meter movements and pointers, as well as in inventory stocking levels at wholesale and resale points in a distribution chain. Keepers of inventories of such meters could maintain an inventory of one particular meter movement and pointer while stocking various scales to meet the various needs to measure particular parameters.